The present disclosure relates to cleaning semiconductor process equipment and more particularly to the cleaning of processed organic polymer deposits using organic solvents.
Most types of dry processing equipment used for the manufacture of semiconductor devices utilize processes involving high temperatures, plasmas and gaseous mixtures for film deposition and etching. During these manufacturing processes, organic and inorganic by-products are deposited on the surfaces of chamber parts. FIG. 1 shows a representative chamber 100 of the prior art used for film deposition and etching that contains deposited by-products 101 on the surfaces of chamber parts. The by-products of a dielectric etch equipment typically contain high concentrations of organic or photoresist-based based polymers and lower levels or metallic or inorganic impurities. Accumulation of these by-products on the surfaces of the chamber parts causes problems in semiconductor manufacturing such as contaminating wafers with particles and organic and metallic impurities. The manufacturing by-products can also interfere with proper semiconductor device manufacturing by altering or stopping process chemistries. As a result, after a certain number of wafers have been processed, these contaminated chamber parts must be removed for cleaning. Effective and appropriate cleaning procedures and recipes are critical in order to obtain clean chamber parts, maximum chamber performance and minimum equipment downtime. In addition, if incorrect cleaning procedures are used, chamber parts can be irreversibly damaged and the lifetime of the chamber parts is significantly shortened.
Previously, organic or photoresist-based polymer deposits were removed using grit blasting, scrubbing with abrasives and carbon dioxide (CO2) blasting. FIG. 2 depicts a typical surface of a chamber part 200 after polymer deposits were subjected to grit blasting, abrasives, or CO2 blasting of the prior art. These physical methods were ineffective in completely removing all organic polymers, leaving portions of organic polymers 202 on the chamber part surface, and resulting in physical damage to the surfaces of the chamber part, such as damaged area 201. As a result, the chamber parts cleaned by these physical methods performed poorly with respect to particles, organic and metallic impurities and often failed prematurely due to deterioration of the surface""s integrity. Additionally, there is no practical way of determining what polymers remain on the chamber part surface after the grit blasting, abrasive or CO2 process is performed and whether the integrity of the chamber part surface is compromised or damaged in some way by these physical process.
What is needed is a method and apparatus for completely removing all process organic polymer deposits from metal chamber part materials as well as metallic impurities such as Al, anodized Al, Ni, stainless steel, Ti, Cu, Cr and Fe. The cleaning method should, in addition to completely removing the organic polymers, also remove particles and metallic impurities without corroding, damaging or altering the original chamber part material and surface morphology. This cleaning procedure should also be applicable to ceramics (Al2O3 and SiC), quartz, glass and silicon.
Additionally, what is needed is to establish criteria to verify that the chamber parts are clean with respect to organic, metallic and particulate impurities and to establish criteria to verify that the physical surface morphology remains intact.
The present invention includes a system and method for cleaning chamber parts with an organic solvent. Preferably, the chamber parts are exposed to the solvent in order to soften or dissolve the organic polymers. The organic cleaning solvent may, for example, be a pyrrole-based, amine-based, or flouro/ether-based or glycol ether acetate-based solvents. This method may be used as a stand-alone method or in conjunction with other prior art methods such as CO2 snow cleaning where that method is used as a pre-process step.
In one embodiment of the present invention, the system uses a solvent dipping method to expose the chamber parts to a liquid phase of the organic solvent. In this embodiment, the chamber part is dipped into a solvent tank containing the solvent. In one variation of this embodiment, the solvent is heated up to a temperature of about 60xc2x0 C.
In another embodiment of the present invention, the system uses a vapor contact system to expose the chamber parts to the organic solvent. In this embodiment, the chamber part is contained within an enclosed environment with a solvent vapor. The chamber part is exposed to the solvent vapor and then cleaned. In one variation of this embodiment, the solvent vapor is heated up to a temperature of about 100xc2x0 C.
An advantage of the vapor contact method is that a chamber part can be kept away from the cleaning solvent which may be saturated with dissolved polymers. This approach will minimize the build-up of polymer impurities in the cleaning solvent tank, and result in cleaner and stain-free chamber parts. The vapor cleaning process also greatly minimizes the amount of solvents used in the cleaning process.
The present invention provides a procedure and apparatus for completely removing all process organic polymer deposits from chamber part materials as well as metallic contaminants such as Al, anodized Al, Ni, stainless steel, Ti, Cu, Cr and Fe used in the making of chamber parts. The present invention also can be used to clean chamber part materials such as ceramics (Al2O3 and SiC), quartz, glass and silicon. The cleaning procedures and systems advantageously remove the organic and/or photoresist-based polymers without corrosion, damaging or altering the original chamber part material or surface morphology.
Additionally, the present invention establishes criteria to verify that the chamber parts are clean with respect to organic, metallic and particulate impurities and establishes criteria to verify that the physical surface morphology remains intact in terms of surface roughness, hardness, thickness and micro-structure.
These and other advantages will become apparent to those skilled in the art after reading the following description and studying the various figures of the drawings.